Flighty
Flighty , adjective
1.
Fleeting; swift; transient.
The flighty purpose never is o'ertook,
Unless the deed go with it.
2.
Indulging in flights, or wild and unrestrained sallies, of imagination, humor, caprice, etc.; given to disordered fancies and extravagant conduct; volatile; giddy; eccentric; slightly delirious.
Proofs of my flighty and paradoxical turn of mind.
A harsh disciplinarian and a flighty enthusiast.